Diabetes is a disease characterized by increases in blood glucose levels caused by an inability to properly produce or respond to insulin. Diabetes is the seventh leading cause of death in the United States and is a leading cause of kidney failure, nontraumatic lower-limb amputations, blindness, heart disease and stroke. In 2010, there were 18.8 million diagnosed cases of diabetes and an estimated 7 million undiagnosed cases in the United States alone (National Diabetes Information Clearinghouse, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH)).